Multishaft gas turbines are used in a number of application including aircraft engines, power generation plants and pipeline compression duty applications. When these gas turbines operate beyond the scope of their design power, the compressors operate beyond the scope of their intended operating conditions, and handling bleed valves are used to restore the compressor operating point to reasonable values. However, these handling bleed valves are can somewhat diminish cycle efficiency.
It is therefore desirable to provide a multishaft gas turbine engine that can restore the compressor operating point to predetermined reasonable values without reducing the cycle efficiency.